(HARRISBURG, PA)—Scientific researchers suggest that a 'perfect storm' of high levels of nitrogen and phosphorus pollution, pesticides, and endocrine disrupting chemicals along with warming water temperatures and parasites are threaten one of Pennsylvania's most popular game fish, the smallmouth bass, according to a new Chesapeake Bay Foundation (CBF) report. Smallmouth bass fishing in Pennsylvania generates $166 million for local economies, supporting 1,300 jobs, according to data from the American Sportfishing Association and the U.S. Fish and Wildlife Service.

"Smallmouth bass are one of the most prized game fish," said CBF President Will Baker. "But in the Susquehanna and other rivers in this region, smallmouth bass are in serious trouble. The good news is that implementing the pollution reduction practices in Pennsylvania's Clean Water Blueprint can make a difference."

The report, Angling for Healthier Rivers, shows the possible link between phosphorus and nitrogen pollution and diseased and dying smallmouth bass. Although notable reductions in phosphorus and nitrogen pollution have occurred in the Susquehanna River since the 1980s data indicates that levels still remain elevated.

Data from the U.S. Geological Survey indicates that between 2007 and 2011, 12 of 24 monitoring sites in the Susquehanna River and its tributaries had levels of phosphorus pollution that were among the highest in the Chesapeake Bay region. In addition 11 of 24 sites had high levels of nitrogen. These pollutants not only can cause algal blooms that trigger spikes in pH levels and low-oxygen conditions that stress fish, they also create conditions that spur the growth of parasites that may be killing young smallmouth bass, new research suggests.

Smallmouth bass are intolerant to many types of pollution and are often likened to the canary in a coal mine by providing scientists with a reliable gauge of water quality—good or bad. Populations in the Lower Susquehanna River in Pennsylvania, the Shenandoah River in Virginia, the South Branch of the Potomac River in West Virginia, and the Monocacy River in Maryland have all experienced disease or die offs in recent years.

Anglers first reported diseased and dying smallmouth bass in the Susquehanna River in 2005. Since that time, catch rates are now a mere 20 percent of what they were before. The situation has become so serious that, to reduce stress on spawning fish, the Pennsylvania Fish and Boat Commission is halting all fishing for smallmouth bass from May 1 until June 15, for the second year in a row. Many fisheries scientists fear a collapse of the smallmouth bass fishery.

"It's almost like you reach a perfect storm situation," said Dr. Vicki Blazer, Research Fisheries Biologists for the U.S. Geological Service, and a lead researcher of the smallmouth bass. "There have been stressors and smallmouth bass have been able to overcome them or deal with them. But eventually, they get to a point where they cannot deal with them anymore."

While Blazer and her colleagues continue to fit these puzzle pieces together, through their work we are beginning to see the bigger picture. The smallmouth is showing us that this amazing natural resource, the Susquehanna River and the life in it, has limits to its resiliency.

"Many factors appear to be affecting the health of the smallmouth bass in the Lower Susquehanna. Of those currently being studied, pollution levels are one we can control," said Harry Campbell, CBF's Pennsylvania Executive Director. "Pennsylvania has made notable progress in the last 25 years, but in order to reduce stress on the smallmouth bass and other aquatic species, we must continue to reduce the amount of pollution getting into the river, and that requires everyone work together."

Pennsylvania and the other Bay states have committed to meeting water quality goals as established in its Clean Water Blueprint—this plan is the Commonwealth's roadmap to lowering pollution in the Susquehanna. When implemented, it will restore water quality in Pennsylvania's rivers and streams.

"Biologically, there is something wrong with these fish, and that speaks to water quality," said Jeff Little, a veteran fishing guide on the Susquehanna. "There are water quality issues that really need to be addressed, and hopefully they will be."

Despite the clear evidence of a problem, Pennsylvania's Department of Environmental Protection (DEP) has determined it is premature to add the Lower Susquehanna to its impaired waters list. The federal Environmental Protection Agency (EPA) is currently reviewing that list and CBF has filed comments calling on EPA to reverse that decision. A determination is expected soon. Last month, the DEP released a detailed plan to study the river and the smallmouth bass population with the involvement of other state and federal agencies and commissions.

"Everyone who values healthy fish and the clean water they need to thrive should be concerned," Baker said. "The Susquehanna needs our help. CBF is encouraged by the Commonwealth's recent actions to ramp up research. But as our report indicates we must continue to implement pollution reduction plans and to commit the necessary resources to clean water programs while studying this complex issue."